Presence of radon in groundwater in parts of Bangalore

Presence of high levels of Radon (²²²Rn) gas was reported from groundwater in Bangalore. To ascertain the ground reality and the nature of the hazards, if any, a study was conducted by the Central Ground Water Board, Bangalore in and around Bangalore city. Groundwater samples from borewells and a dug well were collected and analysed. Available data on Radon gas from both groundwater and surface water sources were also compared. The presence of Radon gas and its concentration in groundwater were examined with respect to geology and well depths. The results are discussed in the paper.     

湖南梅城—寒婆坳地区煤田显微构造成因

从显微尺度分析了湖南梅城-寒婆坳地区岩石中出现较多的显微构造现象,并结合区域构造背景,从宏观和微观角度分析了研究区煤田构造成因。结果表明,研究区以低温脆性变形为主,多组裂隙的交错发育表明了应力场的多期次性,应用缝合线反演得出研究区印支期第Ⅰ期NW-SE向为最大主压应力场,第Ⅱ期NE-SW向挤压应力场次之;平均差应力为50~70 MPa,表明印支期以来煤田构造变形过程中,岩石经历了中等偏低强度的构造应力作用。梅城-寒婆坳地区煤田构造是在脆性-脆韧性变形为主的多期次中等偏低强度的复杂构造运动条件下形成的。      

花岗质岩石中岩石包体研究的新进展

介绍了近年来国内外在花岗质岩石中的岩石包体研究的部分成果，重点论述了利用花岗质岩石中的岩石包体研究岩浆底侵作用、内生成矿作用、岩浆混合作用和区域变质作用等方面的主要进展。     

蒙古国塔木察格盆地塔南凹陷铜钵庙组火山碎屑岩中片钠铝石胶结物的成因

塔木察格盆地塔南凹陷铜钵庙组火山碎屑岩中发育大量的片钠铝石自生矿物。通过偏光显微镜、扫描电镜及X射线衍射分析等,查明了火山碎屑岩中的胶结物与自生矿物类型和成岩共生序列。含片钠铝石火山碎屑岩的成岩共生序列为粘土包壳-方解石-一期微晶石英-一期高岭石-二期微晶石英、二期高岭石、片钠铝石-铁白云石;通过MAT253稳定同位素质谱仪确定了片钠铝石和铁白云石的稳定同位素组成为片钠铝石的δ¹³C_PDB为-8.15‰~-2.81‰,与片钠铝石平衡的CO₂的δ¹³C_CO2为-12.91‰~-7.55‰,通过与海拉尔盆地及BGS盆地系碳氧同位素数据的类比,表明片钠铝石中的碳主要为幔源岩浆来源,形成片钠铝石的钠和铝主要来源于安山岩岩屑、长石晶屑碎屑、玻屑和火山灰等;铁白云石的δ¹³C_PDB为-6.76‰~-2.65‰,与片钠铝石的碳氧同位素数据相似,结合相关地质实例及地球化学模拟实验,可以推断铁白云石中的碳也是幔源岩浆来源,铁白云石中的铁离子主要来源于安山岩岩屑、玻屑、火山灰和蒙脱石等矿物。     

Association of hydrogeological factors in temporal variations of fluoride concentration in a crystalline aquifer in India

The major part of groundwater in India is found in granitic aquifers. Fluoride in groundwater from a crystalline aquifer in a semi-arid region of granitic rocks in India, known as Maheshwaram watershed, was analyzed for spatial and temporal variability during 1999–2002 to assess the effect of hydrogeological factors on fluoride concentration. Samples were collected from 32 representative wells in the area for the pre- and post-monsoon seasons and analyzed for F content. The CHESS computer program was used to calculate ionic activities of aqueous species and the mineral saturation index (SI) for calcite and fluorite. The GARDENIA computer program was used to calculate the recharge values in the study area. The influences of dissolution kinetics of fluoride minerals and recharge from rainfall on fluoride concentration were of interest and results clearly indicate that fluoride content in groundwater depends on the interaction period of groundwater with host rock. Results could also be utilized for designing remedial measures particularly with dilution method in an optimal way.     

Role of superoxide in the photochemical reduction of iron in seawater

We have conducted a series of laboratory studies to investigate the generation of ferrous iron and reactive oxygen species when solutions of seawater containing natural organic matter (NOM) and ferric iron are exposed to simulated sunlight. Total ferrous iron and hydrogen peroxide were measured at nanomolar concentrations with high temporal resolution using chemiluminescence-based methods. In all cases, ferrous iron concentrations rapidly peaked at several nanomoles per litre after a few minutes, and then declined over time, while hydrogen peroxide concentrations increased in a non-linear manner. Although concentrations of both species depended on the concentration of NOM, hydrogen peroxide concentrations were only minimally affected by the presence of iron. Increasing the NOM concentration while the total iron concentration was maintained constant led to an increase in the maximum ferrous iron concentration, suggesting that superoxide-mediated reduction of iron may be a major pathway for ferrous iron formation. This was supported by measurements of superoxide production from irradiation of NOM in the absence of iron and kinetic calculations, as well as an experiment in which superoxide dismutase was added. Further analysis of the data suggested that dissolved oxygen and photo-produced hydrogen peroxide were the primary oxidants of the Fe(II) formed. Thus we propose that superoxide and ferrous iron may be intricately coupled in the system, and that their generation is determined by the supply of NOM available to harvest light and donate electrons.     

X射线荧光光谱分析在我国铁矿石分析中的应用

系统介绍了20世纪90年代以来X射线荧光光谱分析（XRF）在我国铁矿石分析中的应用,包括粉末压片法和熔片法两种最基本的分析手段,主要内容集中在熔片—波长色散X射线荧光光谱分析法在我国铁矿石分析方面的测试技术,重点介绍了熔剂的类型、配比、熔片方法、熔融温度以及钴内标的使用,同时介绍了基体效应校正、谱线重叠校正等方面的内容。     

CSAMT 法在辽西康杖子区深部探矿中的应用

可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。     

辽河双台子河口淤泥质沉积物来源探析

采用化学质量平衡法,分析双台子河口淤泥质沉积物的常量元素特征,并对沉积物来源进行了初步探析。结果表明: 常量元素在沿拦海大坝由北至南方向上变化较为复杂,在向海离岸方向上Al₂O₃、CaO、TFe₂O₃、MgO 等表现为岸边含量较高,向海方向上含量较低,SiO₂的沉积分布与其相反。上述5 种元素具有很好的相关关系,表明了河口沉积物以陆源沉积为主。河口沉积物主要来源于西拉木伦河上游上侏罗统地层区( Ⅱ区) ,该区贡献率达76. 08%,其次为辽河下游第四系沉积物区( Ⅳ 区) ,贡献率达17. 10%。     

Some Measurements of Radon in Soils and in Stream-Water in County Durham

Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters.     

淮北海孜煤矿采煤塌陷区煤矸石充填复垦条件分析

为了增加塌陷区耕地资源,有效地提高土地利用率,减少环境污染,本文通过对海孜煤矿塌陷区进行实地勘查,室内测试和实验,分析塌陷区煤矸石充填复垦条件。分析结果表明:塌陷区的地形地貌条件有利于土地复垦工程的实施,较高的地下水位可以为重构土壤提供充足的水分;塌陷区塌陷深度小,且绝大部分塌陷区已达到稳沉状态,有益于煤矸石充填复垦;大量的煤矸石为充填复垦提供了充足的物质基础,煤矸石中有害元素含量低,复垦后不会对地下水和土壤造成显著的污染,且煤矸石的块度组分有利于水分的保持和上移。     

化学注浆在兴隆庄煤矿西风井深井井筒微裂隙防渗中的应用

兴隆庄煤矿位于地应力较大的地区，由于井壁受力的特点，在第四系与下伏基岩接触的部位，西风井井筒已发生严重的变形破坏。为保证井筒的正常使用，在此部位需要开挖卸压槽以缓冲井筒所受的压力，在开挖卸压槽的过程中，如何防止壁后第四系含水层发生溃砂涌水的事故是一个需要解决的难题。结合工程实例，本文详细地介绍了化学注浆的设计方案及施工工艺，评价了化学注浆的效果，结果表明，化学浆液具有较好的渗透性，能有效的封闭岩层中的微裂隙，达到很好的堵水固砂的效果。     

国产GB-InSAR在特大型水库滑坡变形监测中的应用

水电站库区特大型滑坡的稳定性对于水电站坝工结构及周边人民生命财产安全具有重要影响,对该类滑坡稳定性及变形趋势进行大范围实时精确观测可为滑坡提供可靠的预警和治理信息,具有十分重要的意义。水电站库区滑坡传统监测方法主要以GNSS监测,全站仪监测等为主,本研究将国产先进的地基干涉合成孔径雷达系统LKR-05-KU-S100,应用于澜沧江大华桥水电站沧江桥—营盘滑坡和大华滑坡的监测。现场监测试验表明,该系统精度较高,可进行远距离、全天时、全天候、大范围监测,对于大型及特大型滑坡的监测具有独特的优势和广阔的应用前景。     

Origins of high nitrate in groundwater in Tanzania

Dodoma is located in a semi-arid climate (mean annual rainfall 550 mm) in an area of crystalline basement rock. The groundwater contains high nitrate with NO₃⁻ concentrations averaging 150 mg l⁻¹ and total mineralization between 1000–3000 mg l⁻¹. Factor analysis has been used for the identification of factors that bring about the chemical character of groundwater. Three rotated factors, explaining 77.2% of the total data variance, were extracted. The first factor accounts for 51.0% of the variance and shows high positive correlation with Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, SO₄²⁻, HCO₃⁻ and SEC and is attributed to the leaching of surface and soil salts together with mineral dissolution. The second factor accounts for 14.1% of the variance and is positively correlated with NO₃⁻ and negatively correlated with pH; this is explained by the nitrification process taking place on the sewage effluents. The third factor is highly positively correlated with ¹⁸O and ²H, accounting for 12.1% of the variance and is a consequence of evaporation processes. Nitrate concentrations greater than 100 mg l⁻¹ are commonly found in both deep and shallow groundwaters. It is concluded that the high nitrate concentrations have originated from the sewage effluents that are advecting and dispersing through macropores under bypass flow mechanisms.     

北方干旱区表生介质中金存在形式的研究

对北方干旱区表生介质（土壤或水质沉积物）中的金进行了7种存在形式的研究，结果表明：金主要以自然金相为主（50％）以上，其次为水溶相、吸附相和有机相等。水溶相金在北方干旱气候带普遍存在，说明此自然景观区的金矿床，其表生介质中的金具有明显的溶解作用，呈水溶相金的形式进行迁移。当环境物化条件改变时，金沉淀形成局部富集。应用野外泡塑测金法，金异常衬度大、稳定性好，具有较好的找矿效果。     

MapSUV系统在惠民县土地勘测定界中的应用

该文介绍了土地勘测定界的专业背景知识及MapSUV的相关信息,阐述了MapSUV系统在惠民县土地勘测定界的应用,以及外业获取数据及内业处理的主要工作方法,最后对该系统在土地勘测定界中的应用前景进行了展望。     

我国荒漠戈壁区矿产勘查技术研究与应用现状

由于荒漠戈壁区的地质工作条件恶劣,为减少勘查成本,避免盲目勘查,在该区开展了航卫遥感技术、大深度物探技术(包括航空、地面和地下等空间)、深穿透地球化学勘查方法和非线性理论数据处理方法等应用,目前在岩性构造推断和矿化信息提取等方面取得了一定的进展。     

江苏如东县小洋口地热田成因研究

地热资源按成因可分为对流型地热资源与传导型地热资源两大类。根据地热水的赋存介质差异,传导型地热资源又可分为松散岩类孔隙型、构造裂隙型及古构造面岩溶型3个亚类。小洋口地热田同时存在两种成因地热类型,深部断裂构造带地热水为对流型地热类型,其上部盐城组松散层中的地热水则是其伴生的传导型地热资源。其成因模式是,冷水沿金坛—如皋断裂在自身重力作用下下渗至4～5 km的深部并增温成为高温热水甚至蒸汽,由于密度的减小,其上浮返回浅部裂隙发育处并与其中温度相对较低的热水混合而降温,正由于温度和密度的变化为水的循环提供了动     

槽波地震勘探技术在工作面小构造探测中的应用

小构造是导致煤炭资源回采困难及煤矿安全事故的主要原因。利用槽波地震勘探技术,对义安煤矿11061工作面进行了透射法探测。通过CT成像可以分辨工作面内与煤厚相当的小构造,同时还能获得围岩高应力区及瓦斯富集带等地质信息。探测结果可作为煤矿安全回采的依据。      

静电场轨道阱质谱在水中溶解性有机质表征中的应用进展

溶解性有机质(Dissolved Organic Matter,DOM)在水生生态环境中广泛存在,影响着水环境中多种物质的生物地球化学性质.分析其组成与含量具有重要的生态环境意义,是生态环境科学领域研究的热点.溶解性有机质组成非常复杂,其分子组成的解析一直是难题.近年来,具有高分辨率、高灵敏度、高通量、高扫描速率等特性...